<!DOCTYPE html>
<html lang="zh-CN">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    body {
      background: #000;
      text-align: center
    }

    #c1 {
      background: #fff;
    }
  </style>

</head>

<body>
  <canvas id="c1" width="800" height="600">

  </canvas>
</body>
<script>
  let oC = document.getElementById('c1');
  let gd = oC.getContext('2d');       //图形上下文-绘图用的接口


  //  路径操作-跟ps里的选区一样
  gd.moveTo(100, 100);                    //起点
  gd.lineTo(200, 200);                     //前往哪个点
  gd.lineTo(130, 200);
  gd.lineTo(100, 100);

  gd.strokeStyle = 'red';                   //描边颜色
  gd.stroke();
  gd.fillStyle='red';                     //填充
  gd.fill();





</script>

</html>